Mosquito Repellents

There is no doubt about mosquitoes and mosquito bites are annoying. The nuisance mosquitoes bother people around homes or in parks and recreational areas and everywhere. They reduce real estate values, adversely affect tourism and related business interests, or negatively impact livestock or poultry production. Above all these, mosquitoes transmit fatal diseases like Dengue fever, Malarial fever, Filariasis,Chikungunya, Encephalomyelitis etc.

Mosquitoes have complex methods of detecting hosts and different types of mosquitoes react to different stimuli. Most mosquitoes are active at dawn and dusk, but there are also day biting mosquitoes. There are many factors that attract mosquitoes towards you.

1. Body Temperature

The exact body temperature depends on the type of mosquito. Many mosquitoes are attracted to the slightly cooler temperatures of the extremities of the body.

2. Carbon Dioxide

Carbon dioxide content in the body attracts mosquitoes. Carbon dioxide content in the closed room also attracts mosquitoes.

3. Moisture

Mosquitoes are attracted by perspiration because of the chemicals it contains and also because it increases the humidity around your body. Interior plants, aquarium etc attracts more mosquitoes.

4. Lactic Acid

Lactic acid content of the body is another attractant. Lactic acid content in the blood increases after exercise and also after eating salty and high potassium food materials.

5. Perfumes and Flowers

Perfumes, floral decorations, cosmetics, fragrant cloths etc attract mosquitoes

6. Dark Clothing

Dark cloths attract mosquitoes because they can easily locate the host from the surroundings. They have feeble vision.

Mosquito bite

Mosquitoes have chemo sensors which enables them to detect the humans or any other animal by the odor, heat released by the body and also the carbon dioxide exhale by the humans and the other animals. Mosquito bites are caused only by the bite of a female mosquito. The female mosquito feeds off our blood by piercing the skin with the proboscis a modified mouth part. While sucking our blood, mosquito deposits some saliva into the skin. The saliva contains anticoagulant proteins that remain in our body and react with the body chemicals, resulting in the characteristic itching and bump.

Mosquito Repellents

Various natural and synthetic chemicals are used to repel mosquitoes from our surroundings. These chemicals in the form of vapors block the chemo reception and also the respiratory tracts of the mosquitoes and thus they avoid the hostile situation.

Natural Repellents

Most common natural repellents used are oils extracted from plants. These natural products will effectively repel mosquitoes, but they require more frequent reapplication (at least every 2 hours). Citronella Oil, Lemon, Eucalyptus Oil, Cinnamon Oil, Castor Oil, Rosemary Oil, Lemongrass Oil, Cedar Oil, Peppermint Oil, Clove Oil, Garlic Oil etc are found to be effective against mosquitoes.


It is a plant-derived substance, used as an insecticide. Pyrethrum comes from the flowers of the daisy Chrysanthemum cinerariifolium. Pyrethrum and its modified forms are used to prepare mosquito coils.mats liquids etc. Natural pyrethrins are highly fat soluble, but are easily degraded and thus do not accumulate in the body.

Synthetic Repellents

The Pyrethrins are a pair of natural organic compounds that have potent insecticidal activity Pyrethrin I and pyrethrin II are structurally related esters with a cyclopropane core. They are viscous liquids that oxidize to become inactivated. They are non-persistent, being biodegradable, and break down on exposure to light or oxygen.

Synthetic Pyrethroids

Synthetic Pyrethroids, is the synthetic form of Pyrethrum found in the chrysanthemum flower. The compounds have low toxicity for humans and birds, and are used in many household insecticides such as RAID as well as mosquito coils. They act by paralyzing the insect before it kills. They are also used as an ultra low volume (ULV) spray for outdoor mosquito control.


The Allethrins are a pair of related synthetic compounds used in insecticides. They are synthetic pyrethroids is used mainly for the control of flies and mosquitoes in the home, flying and crawling insects on farm animals, and fleas and ticks on dogs and cats. It is formulated as aerosols (1 – 6 g/litre), sprays, dusts (1%), smoke coils, and mats. It is used alone or combined with synergists (e.g.piperonyl butoxide and N- octylbicycloheptene dicarboximide) or other insecticides (e.g., fenitrothion). It is also available in the form of emulsifiable concentrates and wettable powders.


Bioallethrin is more than twice as effective as allethrin and is mainly used to control household insects. It is formulated as aerosols and sprays with synergists and/or other insecticides (e.g., d-phenothrin or deltamethrin).

DEET (N,N-diethyl-m-toluamide),

DEET is the most common active ingredient proven to prevent mosquito bites. It is a member of the toluene chemical family and DEET is slightly yellow liquid at room temperature and can be prepared by converting m-toluic acid to acyl chloride and reacting with diehtylamine.

Mosquito mats

Mosquito mats are available as chips. The chemicals are coated as thin layers on both sides of the chip. The chips are heated in an electronic heater and the vapor repels mosquitoes.

Liquid Vaporizer

Liquid repellents are widely used to repel mosquitoes. Various brands are available in the market with refills and vaporizers. The Liquidator mosquito repellent has a graphite rod in the middle and the bottle is filled with the repellent. There is a heater coil in the liquidator. The repellent consist of the chemical which when come in the contact of the heated rod produce fumes which disable the sensors of the mosquitoes. The fumes produced by the repellent block the chemosensors of mosquitoes so that they cannot identify human beings.

Liqiud mosquito repellents contain any one of the chemical such as Prallethrin ,Prallelthrin ,Allethrin etc.Of these the most commonly used one is Pralletrhin.


Prallethrin is a pyrethroid chemical used as an insecticide. It is an Yellow to amber viscosity liquid.d -trans-Prallethrin is a potent contact insecticide which produces a rapid knock-down, with same chemical and physical properties as Prallethrin,.d-trans-Allethrin and powerful repellent used in mosquito coil and liquid.


The chemical repellents used as mosquito repellents are toxic substances. Even though the concentration of the ingredient is in a safe level, this may cause allergic and respiratory problems in some persons. Precautions are recommended by the manufacturers and these include

1. Avoid inhalation and skin contact.
2. Wash contaminated skin & eyes.
3. Destroy empty containers after use.
4. Keep away from food stuff and animal feeds.

One response to “Mosquito Repellents

  1. Dear Dr. Kumar,

    Your article is very informative. Would really appreciate if you could help me with a few questions. Have been unable to find any information on this topic (except for your blog).

    Is it safe to use the liquid vaporizers such as All-Out which have 2.4% Prallethrin. Is it safe to use them in air conditioned rooms for long periods (8-10 hours) . What about usage for infants and/or pregnant women?

    Thanks in advance